1. Field of the Invention
The present invention relates generally to a multi-band antenna, and more particularly to a multi-band antenna used in an electric device.
2. Description of the Prior Art
In recent years, developments of portable wireless communication devices are speeded up. Considering the competitiveness, an antenna built in the device must have small size to save space and increase convenience.
A planar inverted-F antenna is always used inside an electric device. The inverted-F antenna usually comprises a first radiating element, a second radiating element extending from said first radiating element along a direction away from the first radiating element, a connecting element with an end connecting to the connection of the first and second radiating element, a grounding element connecting to the other end of the connecting element and a feed line linking to a feeder point on the connecting element. The current goes from the feeding point through the first radiating portion to operate in a first frequency band, and through the second radiating portion to operate in a second frequency band. TW Patent No. 1240450, which was issued to Cheng on May 1, 2005, discloses an antenna as above.
However, if the antenna works on a low frequency band, the length of the radiating element could be too long to adapt for present electronic device.
Hence, in this art, an improved antenna to overcome the above-mentioned disadvantages of the prior art should be provided.